Editing 7-Dehydrocholesterol (section)

==Location ==
The skin consists of two primary layers: an inner layer, the [[dermis]], comprising largely [[connective tissue]], and an outer, thinner [[Epidermis (skin)|epidermis]]. The thickness of the epidermis ranges from 0.04&nbsp;mm to greater than 0.6&nbsp;mm.<ref>{{Cite journal |last=Lintzeri |first=D.A. |last2=Karimian |first2=N. |last3=Blume‐Peytavi |first3=U. |last4=Kottner |first4=J. |date=2022 |title=Epidermal thickness in healthy humans: a systematic review and meta‐analysis |url=https://onlinelibrary.wiley.com/doi/10.1111/jdv.18123 |journal=Journal of the European Academy of Dermatology and Venereology |language=en |volume=36 |issue=8 |pages=1191–1200 |doi=10.1111/jdv.18123 |issn=0926-9959|doi-access=free }}</ref> The epidermis comprises five ''strata''; from outer to inner, they are the [[stratum corneum]], [[stratum lucidum]], [[stratum granulosum]], [[stratum spinosum]], and [[stratum basale]]. The highest concentrations of 7-dehydrocholesterol are found in the epidermal layer of skin—specifically in the stratum basale and stratum spinosum.<ref name="Norman_1998">{{cite journal | vauthors = Norman AW | title = Sunlight, season, skin pigmentation, vitamin D, and 25-hydroxyvitamin D: integral components of the vitamin D endocrine system | journal = The American Journal of Clinical Nutrition | volume = 67 | issue = 6 | pages = 1108–1110 | date = June 1998 | pmid = 9625080 | doi = 10.1093/ajcn/67.6.1108 | doi-access = free }}</ref> The production of pre-vitamin D<sub>3</sub> is, therefore, greatest in these two layers.